1. Field of the Invention
This invention relates generally to low core loss flux transformers, and more specifically, to such transformers that have a rotating flux vector for saturating the core to reduce hysteresis losses.
2. Description of the Prior Art
It is well known that transformer cores experience two types of losses: hysteresis losses and eddy current losses. Hysteresis losses represent the energy expended in reversing the magnetic moments of the core when the core is subjected to an ac field. It is well known that the hysteresis losses can be reduced to zero by subjecting the magnetic core to a rotating magnetic induction at the saturation level. Eddy currents are established in the magnetic core by the changing magnetic field, and energy is lost as heat by the circulation of eddy currents in the core. Some core materials wth high resistivities, such as ferrites and amorphous metals, have naturally low eddy current losses. Hence, a rotating saturated induction vector generates very low total losses in these materials. Further, amorphous metals have an anomalously high eddy current loss under unidirectional ac flux conditions associated with the size of their magnetic domains. By operating at saturation with a rotating flux, these domains and their associated losses are eliminated.